As shown in FIG. 1, a currently available conventional inflation valve 10 provided on a tire or an inflatable mattress has an internal pin valve body 12, and an external locating member 14 provided around a lower end of the inflation valve 10 for firmly connecting the inflation valve 10 to an opening 720. The opening 720 may be formed on a wheel rim 700 of a tire, for example. A user may connect a pumping device (not shown) to an upper end of the inflation valve 10, so that the pin valve body 12 is triggered by the pumping device to release an airtight state in the inflation valve 10, allowing the pumping device to pump air into the tire via the inflation valve 10.
The pin valve body 12 on the conventional inflation valve 10 only allows air to flow in one way. When a user wants to pump a tire, for example, to a fixed pressure level, a pressure gauge is usually connected to the pumping device before pumping, so that the internal pressure of the tire may be detected in real time to avoid, an excessively or insufficiently pumped tire that causes dangers in driving.
In the detection of tire pressure with a pressure gauge externally connected to the pumping device, the detected pressure is affected not only by the accuracy of the pressure gauge, but also by the operating skill of the gauge user. That is, it is uneasy to always maintain the accuracy of the detected pressure at a preset level. An unbalanced, an exceeded, or an insufficient tire pressure would very possibly seriously endanger a driver's safety and even life in the course of driving.